Teeth Analysis Reveals Early Life Dietary Transitions

NIEHS-supported researchers report that the ratio of barium to calcium in teeth can accurately reflect an infant’s dietary transition from the introduction of mother's milk through weaning. This work identifies a new biomarker that could be useful for epidemiologic investigations of the health consequences of breastfeeding and chemical exposures during early life and for determining developmental transitions in primates.

The researchers investigated the spatial distribution of barium/calcium in teeth using laser ablation-inductively coupled plasma-mass spectrometry for high-resolution elemental analysis. They analyzed teeth from macaques with known diet histories as well as teeth shed by children enrolled in the University of California Berkeley's CHAMACOS Study , where breastfeeding and infant formula use were prospectively recorded. The analyses showed that the ratio of barium/calcium in teeth reflected the barium intake via mother’s milk and could be used to determine the exact timing of birth, when the infant was fed exclusively on mother’s milk, and the weaning process. The researchers also documented the first early-life dietary transition in a juvenile Neanderthal by applying the technique to a several thousand-year-old Neanderthal tooth.